Pfizer Inc. and Alliance Foundation Trials, LLC announced results from the Phase 3 PATINA trial demonstrating that the addition of IBRANCE® (palbociclib) to current standard-of-care first-line maintenance therapy (following induction chemotherapy) resulted in statistically significant and clinically meaningful improvement in progression-free survival (PFS) by investigator assessment in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC). In the study, which is sponsored by AFT, median PFS was 44.3 months (95% CI: 32.4-60.9) for patients treated with IBRANCE in combination with anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapy, and 29.1 months (95% CI: 23.3-38.6) for patients treated with anti-HER2 therapy and endocrine therapy alone [HR: 0.74 (95% CI, 0.58-0.94); unstratified 1-sided p= 0.0074]. This represents an extension in median PFS of over 15 months. Overall survival, a secondary endpoint, was not yet mature at the time of the analysis. These results are being presented during a late-breaking oral session (Abstract GS2-12) and highlighted in the press program at the 47th San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Texas.
“PATINA is the first large Phase 3 study to show the benefit of CDK4/6 inhibition in HR-positive, HER2-positive metastatic breast cancer,” said Otto Metzger, M.D., principal investigator of the trial for Alliance Foundation Trials and Medical Oncologist at the Dana-Farber Cancer Institute. “These results support the potential of this maintenance treatment to slow disease progression and improve clinical outcomes in this patient population.”
Approximately 10% of all breast cancers are HR+, HER2+i , which is sometimes referred to as double-positive or triple-positive breast cancer. Despite advances in treatment, the development of resistance to anti-HER2 and endocrine therapy is a challenge, and novel therapeutic approaches are needed for HR+, HER2+ MBC.ii IBRANCE is not currently indicated for HR+, HER2+ MBC.
“IBRANCE, the first CDK4/6 inhibitor, revolutionized the treatment of HR-positive, HER2-negative metastatic breast cancer, and has been prescribed to over 773,000 patients since its initial approval in 2015,” said Roger Dansey, M.D., Chief Development Officer, Oncology, Pfizer. “These results demonstrate that the addition of IBRANCE to standard of care shows promise as maintenance therapy in HR-positive, HER2-positive disease. PATINA underscores Pfizer’s ongoing commitment to addressing the unmet needs of people with breast cancer, and we look forward to discussing the results with regulatory authorities.”
The safety and tolerability of IBRANCE in the PATINA study was consistent with its known safety profile in HR+, human epidermal growth factor receptor 2-negative (HER2-) MBC, and no new safety signals were identified. The most common adverse events observed with IBRANCE were hematologic toxicities, such as neutropenia and leukopenia. Non-hematologic adverse events included fatigue, stomatitis and diarrhea, which were generally mild to moderate in severity.
Since its initial regulatory approval in 2015, IBRANCE continues to be a standard-of-care first-line treatment for HR+, HER2- MBC and has been approved in more than 108 countries. Pfizer plans to share the results from PATINA with regulatory authorities.
About the PATINA Trial
PATINA (AFT-38) is a randomized, open-label Phase 3 study to evaluate the efficacy and safety of IBRANCE® (palbociclib) in combination with anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapy compared to anti-HER2 therapy and endocrine therapy alone as a first-line maintenance therapy (following induction chemotherapy treatment) for patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC). While Pfizer is providing funding support for the trial, PATINA is sponsored by Alliance Foundation Trials, LLC (AFT) in collaboration with six international cancer research groups in the U.S., France, Germany, Italy, Spain, Australia, and New Zealand.
Study participants who were previously treated with anti-HER2 therapy were randomized to receive IBRANCE, in addition to anti-HER2 therapy and endocrine therapy (n=261), or anti-HER2 therapy and endocrine therapy alone (n=257). The primary endpoint is progression-free survival (PFS) as assessed by the investigator. Overall survival is a secondary endpoint.
About IBRANCE® (palbociclib)
IBRANCE is an oral inhibitor of CDKs 4 and 6,iii which are key regulators of the cell cycle that trigger cellular progression.iv,v In the U.S., IBRANCE is indicated for the treatment of adult patients with HR+, HER2- advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy in postmenopausal women or in men; or with fulvestrant in patients with disease progression following endocrine therapy.
